HUMAN RESEMBLANCES TO LOWER LIFE. 5 



ledge of butterfly-anatomy, however, soon dispels any doubts one 

 may have entertained regarding the relationship of the insect with 

 the shrimp. For we discover, firstly, that the body of the butterfly 

 is constructed of segments or joints, corresponding in structure, as 

 they practically agree in number also, with those of the shrimp. 

 Again, the appendages of the butterfly, though specially modified 

 for its aerial life and for its work of flower-visitation, present us 

 with a type which is essentially that seen in the curious jaws, jaw- 

 feet, and legs of the armoured crustacean. Lastly, but by no means 

 the least convincing proof of the unity of type which underlies 

 the apparent dissimilarity in form and life, we find the personal 

 belongings of the butterfly to present us with an exactly similar 

 arrangement to that seen in the shrimp. The insect-heart pulsates 

 just beneath the covering of its back ; the digestive system occupies 

 the middle region of its frame ; and the nervous system, presenting 

 us again with the double-chain type, lies along the floor of the insect- 

 body. Not only does our discovery of the remarkable similarity of 

 type teach us that the Crustacean host and all butterflies possess 

 bodies which are built up on one and the same type, but we also 

 learn that what holds true of the relations of one shrimp to others 

 and to all its neighbour crustaceans is likewise true when we con- 

 sider how butterflies are related to their insect neighbours. Each 

 one of the thousands of existing insect species presents us with a 

 body essentially similar to that of our butterfly in its broad details. 

 Where differences exist, they are referable to the modifications of one 

 and the same plan, and are not produced by the inauguration of new 

 plans or fresh types. All insects are therefore found to be modelled 

 on the type we discover underlying the butterfly's personal anatomy. 

 It is therefore no transcendental dream, but a sober fact of zoology, 

 that by constructing the figure of a jointed animal with its appen- 

 dages, with a back-heart, a nervous system below, and a digestive 

 tube running through the middle of its body, we should represent 

 the archetype, so to speak, at once of the insect class and of the 

 crustacean tribes. Furthermore, it would be easy to add other 

 important facts which rest on a similar basis to those just described. 

 All worms, spiders, mites and scorpions, and centipedes, conform to 

 the plain archetype we see in shrimp and butterfly. So that when, 

 to return to Cuvierian axioms, we speak of the '"Articulated" or 

 " Annulose " animals, forming one of the chief and primary divisions 

 or " types " into which the animal kingdom has been parcelled out 

 by Nature, we are only reiterating the facts taught us by our examina- 

 tion of the shrimp and butterfly. One and the same fundamental 

 idea is thus found to underlie the often wide dissimilarities of animal 

 life ; and it is puzzling to say whether we are most liable to be struck 

 by the unity which prevails beneath the diversity of the animal 



